The present invention relates generally to refrigerated display merchandisers of the type used in supermarkets, mini-marts, convenience stores and other commercial establishments for displaying and merchandising refrigerated or frozen products for sale. More particularly, the present invention relates to open-front refrigerated display merchandisers of the type wherein a curtain of cold refrigerated air is passed generally downwardly across the open front product display region of the merchandiser.
Refrigerated display merchandisers, also commonly referred to as display cases, having open front display regions are commonly used in supermarkets, mini-marts, convenience stores and other commercial establishments for displaying and merchandising refrigerated or frozen products for sale. The open front nature of such display cases permits the consumer to simply reach into the product display region to select and remove a product for purchase without the inconvenience of needing to open a door to access the product. Customarily, a curtain of cold refrigerated air is passed generally downwardly at a set velocity across the open front of the display case to form an invisible boundary between the product display region and the region of the store in front of the display case. This air curtain not only helps retain cool refrigerated air within the product display region of the display case, thereby cooling the display product on the shelves of the display case, but also functions to isolate, to a certain extent, the product display region from the ambient air within the store. Ambient air that does enter into open product display region undesirably causes increased energy consumption by increasing the cooling demand on the refrigeration system associated with the display case. Further, such ambient air may also cause a local temperature rise within the product display region sufficient to result in an undesirable rise in product temperature that could adversely impact upon product quality.
Significant intrusion of ambient air into the interior of the display case occurs when consumers reach into the product display region to select and remove product. Customers walking by the open front of the display case may also disturb the integrity of the air curtain, resulting in intrusion of ambient air from the store into the product display region. To reduce the amount of intrusion and ensure rapid reestablishment of the air curtain, it is common practice to maintain the air curtain at a relatively high velocity. As the volume of air being supplied to generate the air curtain is directly proportional to the required velocity of the air curtain, maintaining a relatively high velocity for the air curtain requires greater energy consumption, which increases store operational costs. Therefore, it would be desirable to reduce the energy consumption by lowering overall energy consumption in generating the air curtain.
It is an object of the present invention to provide a refrigerated merchandiser including an improved air curtain system that consumes less energy overall. It is a further object of the present invention to provide a refrigerated merchandiser including a air curtain system wherein the velocity of the air curtain is varied between a relatively lower velocity maintained during steady-state operation and a relatively higher velocity in response to a sensed disturbance in the air curtain or sensed motion in front of the display case.
The refrigerated merchandiser of the present invention includes a display case defining a product display region having an open-front isolated from the ambient air of the store by means of at least one generally downwardly directed air curtain of relatively cold refrigerated air. In accordance with the present invention, a sensor is positioned in operative association with the display case to sense a disturbance in the air curtain or to detect consumer activity in the store region immediately in front of the product display case. The sensor provides an output signal to a controller, the output signal indicating the existence of a disturbance in the integrity of the air curtain or motion in the monitored region depending upon which of the aforementioned sensors is installed. The controller in turn operates to increase the velocity of the air curtain from a relatively lower velocity maintained during steady-state operation to a relatively higher velocity.